Titanium, titanium based alloy, nickel based alloy, and stainless steel castings are used in large numbers in the aerospace industry. Many such castings are made by the well known investment casting process wherein an appropriate melt is cast into a preheated ceramic investment mold formed by the lost wax process. Although widely used, investment casting of complex shaped components of such reactive materials can be characterized by relatively high costs and low yields. Low casting yields are attributable to several factors including surface or surface-connected, void type defects and/or inadequate filling of certain mold cavity regions, especially thin mold cavity regions, and associated internal void, shrinkage and like defects.
Lower cost casting of reactive metals and alloys such as titanium and titanium and nickel based alloys using permanent, reusable, multi-part metal molds based on iron and titanium is described in Colvin U.S. Pat. No. 5,287,910. Casting of aluminum, copper, and iron based castings using permanent metal molds is described in U.S. Pat. No. 5,119,865.
It is an object of the present invention to provide die casting apparatus and method for casting metals and alloys, especially metals and alloys reactive to oxygen, under relatively high vacuum die cavity conditions.
It is another object of the present invention to provide die casting apparatus and method for casting metals and alloys under relatively high vacuum die cavity conditons followed by removal of the die cast components from the dies to the ambient atmosphere and quenching of the components in a quenchant medium proximate the dies.